Identity-Based Public Multi-Replica Provable Data Possession

Cloud storage has been gaining tremendous popularity, which provides facilitative data storage and sharing services for distributed clients. To maximize the availability and reliability, some customers may store multiple replicas of critical data on cloud servers. However, cloud servers may collude to make it look like they are storing multiple copies of data, whereas in fact they only store a single copy. Currently, several multi-replica provable data possession schemes have been proposed to provide verifications to ensure that all the outsourced copies are actually stored and maintained intact. For these schemes with third-party verifications, correctly choosing public keys of data owners relies on the public key infrastructure (PKI), which is complicated and resource consuming. In this paper, we propose a novel identity-based public multireplica provable data possession scheme (IDPMR-PDP) to provide third-party verification of outsourced data with multiple replicas without PKI. We also introduce a formal security model of identity-based public multi-replica PDP schemes and prove that the IDPMR-PDP is secure against malicious cloud servers and privacy-preserving against curious verifiers under this model. Meanwhile, our analyses and simulation results demonstrate that the IDPMR-PDP realizes efficient integrity verification.